1. Field of the Invention
This invention relates to a machine tool system, and more particularly to a mechanism for securely clamping a cutting tool holder in a cutting machine.
2. Prior Developments
U.S. Pat. No. 5,193,954, issued to Carl Hunt on Mar. 16, 1993, discloses a machine tool system that comprises a clamping device mounted in the head of a cutting machine. The machine head can be rotating or non-rotating.
The clamping device has a socket adapted to receive therein a cutting tool holder, whereby various different cutting tools can be selectively mounted on the cutting machine head.
The cutting tool holder comprises a tubular section having a frusto-conical outer surface adapted to seat against a conical socket surface. The inner surface of the tubular section forms an annular lip that is engageable with individual wedge lock elements that are radially movable to exert axial lock forces on the tubular section of the cutting tool holder. An axially movable drawbar is provided to move the wedge lock elements into or out of engagement with the annular lip on the tool holder.
The tool holder has a wedge lock fit in the frusto-conical socket of the clamping device, whereby the tool holder has a secure non-wobbling securement in the clamping device. However, it is also necessary to provide a clutch means between the clamping device and tool holder in order to prevent circumferential slippage between the tool holder and clamping device. In the machine tool system shown in U.S. Pat. No. 5,193,954, the clutch means comprises an annular toothed member bolted onto an internal end surface of the clamping device. The tubular section of the tool holder has multiple grooves in its end surface that fit onto the teeth of the annular toothed member, to establish a non-slip drive connection between the clamping unit and tool holder.